Teses / dissertações sobre o tema "Dilution"

Ce travail presente une solution aux multiples problemes poses par le pilotage informatique d'un ensemble cryogenique a dilution, son objectif a ete d'en simplifier la mise en uvre et l'exploitation. Cette etude a ete realisee dans un groupe de physique des hautes energies. Ce groupe est engage dans le developpement de nouvelles techniques de detection de particules, a basse temperature, pour la recherche de la matiere noire et pour la mesure des neutrinos solaires. Le memoire rappelle les fondements de la physique a basse temperature, les principes des cryostats a helium 4 et a dilution. Le systeme cryogenique utilise y est decrit en detail. Ce rapport presente ensuite une description des methodes de mesure et de regulation de temperature generalement employees en cryogenie. La encore, le systeme de mesure de temperature realise au lapp est decrit de facon circonstanciee. Ce memoire montre aussi une vue de l'ensemble des equipements mecaniques et electroniques utilises, ainsi qu'une description du developpement informatique realise. Enfin, le memoire propose un bilan de l'informatisation et des ameliorations qu'il est possible d'apporter a celle-ci

The aim of this thesis was to develop a simple usable kinetic scheme for protein refolding that was not dependent on reactor type, and to estimate the relative effect of mixing on refolding and aggregation. There are few direct comparisons between experiments and simulations for fed-batch or continuous refolding, and only batch-derived kinetic schemes are available for use in these reactors. Their applicability has not been tested in alternative reactor types. The effect of mixing on refolding and aggregation has also largely been ignored. However aggregation is likely to be affected by the efficiency of mixing due to the higher-order dependence of the aggregation reaction and the complex dependence of refolding and aggregation on denaturant concentration. A statistical design refolding experiment was first conducted with recombinant trypsinogen inclusion bodies to assess the effects of various physical refolding parameters. Mixing was shown to be important. The existing batch-derived kinetic scheme for lysozyme refolding was then examined in detail and shown to not predict refolding yield in a fed-batch reactor. An improved kinetic scheme was developed using a novel labelling technique, and stopped-flow classic light scattering to directly measure the aggregation rate constant. The model involves a sequential aggregation mechanism in competition with early commitment to refolding, and gave an improved estimate of lysozyme fed-batch refolding yield. An optimum level of mixing was identified for lysozyme dilution refolding using an oscillating grid reactor. An analysis of a diffusive mixing model combined with the improved kinetic scheme demonstrated the effect of varying mixing length-scales on refolding yield, and partly explained the optimum mixing level identified with the oscillating grid experiments. The key outcomes of this thesis are an improved kinetic scheme for lysozyme refolding, and a better understanding of the effects of mixing.

Thesis (PhD)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: The Constitutional Court in the Republic of South African indicated in 2006 (Laugh It Off Promotions CC v SAB International (Finance) BV t/a Sabmark International (Freedom of Expression Institute as amicus curiae), 2006 (1) SA 144 (CC)) that a senior trademark cannot be provided with anti-dilution protection if the senior trademark cannot demonstrate a probability of substantial economic harm. In the United States of America, legislation (Trademark Dilution Revision Act of 2006) corrected an earlier Supreme Court decision (Moseley v Victoria's Secret Catalogue, Inc., 537 U.S. 418 (2003)), and as a result evidence of a probability of dilution is now required to provide a senior trademark with anti-dilution protection. Senior trademarks experienced mixed success in courts in the Republic of South Africa as well as the United States of America when requesting anti-dilution protection. The reason is that when empirical evidence is offered of trademark dilution the nature of the evidence is usually limited and the method of obtaining it is often flawed. The response of brand managers to trademark infringement also seems to be limited to decisions contemplating litigation. Therefore, to assist both the legal and marketing fraternity when trademark infringement is thought to occur, this study investigates the nature and extent of trademark dilution. A literature review revealed the elements and forms (tarnishing and blurring) of trademark dilution and the motivation for using the concept ‘brand’ and the construct ‘brand equity’ to conceptualise trademark value. The limitations of previous research in measuring trademark dilution and commentary on court decisions provided the basis of the conceptualisation of trademark dilution as an undesirable effect on customer-based brand equity, operationalised as brand attitude. Brand attitude is a higher level brand value creator and five sub-components (affect, cognition, attitude valence and stability, attitude accessibility, purchase intention) were identified that measures brand attitude accurately. Brand attitude is also preceded by brand familiarity and leads to brand loyalty. Furthermore, brand attitudes can also be explained according to four types of decision-making processes: the type of decisions (high and low involvement) and type of motivations (informational and transformational). The purpose of this study was to investigate the nature and extent of trademark dilution, (tarnishing and blurring) on components of customer-based brand equity. The study used an experimental research strategy and an electronic survey instrument (Qualtrics) with self-administered questionnaires. Six hypotheses were formulated to assess whether trademark tarnishing and blurring had an effect on any component of customer-based brand equity when trademarks/brands were considered collectively and individually. The study was designed as a 3 x 2 x 2 factorial experiment. It consisted of three factors (type of dilution; type of decision; type of motivation) with different levels (undiluted/tarnish/blur; high involvement/low involvement; informational/transformational). Twelve different questionnaires were administered to a convenience sample of 3 441 potential respondents. The data generated by the 12 questionnaires was analysed using ANOVA and Mann-Whitney U tests. The results suggested that trademark tarnishing did have statistically significant effects on components of customer-brand equity as far all trademarks/brands were concerned and that the effect of trademark tarnishing and blurring were different when all trademarks/brands were considered together. Tarnishing and blurring had statistically significant effects on components of customer-based brand equity when individual trademarks/brands were considered, but the effect seemed to be specific to the type of decision (high/low involvement) taken and not the type of motivation (informational/transformational) involved. Tarnishing and blurring, when compared, had different and similar, but varying in intensity, effects on components of customer-based brand equity for individual trademarks/brands. Tarnishing and blurring, when considered separately, had different and similar, but varying in intensity, effects on components of customer-based brand equity. The study made a theoretical contribution which should be of value to members of the legal and marketing fraternity. The study showed in the first instance that trademark tarnishing and blurring are independent constructs that had different or similar, but varying in intensity, effects on components of customer-based brand equity. The effect of trademark dilution, tarnishing and blurring, is not limited to brand recall and recognition and brand attitude accessibility. Trademark tarnishing also had different or similar, but varying in strength, effects on individual trademarks/brands, as did trademark blurring. The type of decision (high or low) and type of motivation (informational or transformational) therefore play a role in the unique effect trademark tarnishing or blurring will have on components of customer-based brand equity. Secondly, the effect of trademark tarnishing and blurring may not be unfavourable by implication. In fact, blurring had a positive effect on components of customer-based brand equity, at least after a single exposure. This finding implies that trademark tarnishing has a more severe and faster effect on customer-based brand equity compared to trademark blurring. A brand manager will, as a result of the study, know how to respond, if at all, when a junior mark emerges that is similar to their senior trademark and seemingly dilutes the senior trademark. An attorney whose client requests anti-dilution protection will know, as a result of the study, whether litigation is indeed the answer to the problem. The study provides insight, not only regarding the nature of trademark dilution, as explained by the impact of trademark tarnishing and blurring on specific components of customer-based brand equity, but also regarding the extent of trademark dilution. Trademark dilution has an effect on trademarks/brands, but the effect, be it in respect of a specific component or the intensity of the effect on the component, may not be what is expected. Based on the results of this study several recommendations can be offered to brand managers and trademark attorneys. Brand managers (senior trademarks) should not respond to junior marks using their brands (senior trademarks) without first assessing the nature and extent of the effect of the junior mark on the senior trademark’s customer-based brand equity. Similarly, attorneys should also first examine the nature and extent of trademark dilution and advise their clients accordingly. Once the nature and extent of trademark dilution have been determined, a brand manager can customise his response according to the component of customer-based brand equity affected as well as the intensity of the effect. Attorneys can support at least part of their arguments to obtain anti-dilution protection for their clients, on very exact indications of the effect of use by a junior mark on customer-based brand equity.
AFRIKAANSE OPSOMMING: Die Konstitusionele Hof van die Republiek van Suid-Afrika het in 2006 (“Laugh it Off Promotions CC vs SAB International (Finance) BV t/a Sabmark International (Freedom of Expression Institute as amicus curiae),” 2006 (1) SA 144 (CC)) bevind dat ‘n senior handelsmerk nie anti-skendingsbeskerming kan geniet tensy die senior handelsmerk ‘n waarskynlikheid van wesenlike finansiële skade kan demonstreer nie. In die Verenigde State van Amerika het wetgewing ‘n Hooggeregshof-uitspraak (“Moseley v Victoria’s Secret Catalogue, Inc.,” 537 U.S. 418 (2003)) gekorrigeer sodat sederdien slegs bewys van ‘n waarskynlikheid van skending nou benodig word vir ‘n senior handelsmerk om anti-skendingsbeskerming te kan geniet. Senior handelsmerke het gemengde welslae in beide die Republiek van Suid-Afrika sowel as die Verenigde State van Amerika behaal wanneer hulle anti-skendingsbeskerming versoek het omrede die empiriese bewyse wat normaalweg aangebied is, beperkend van aard was en die data-insamelingsmetode gebrekkig. Die reaksie van handelsmerkbestuurders op handelsmerk-oortreding was tot dusver beperk tot besluite ten gunste van litigasie al dan nie. Derhalwe ondersoek hierdie studie die aard en omvang van handelsmerk-skending om sodoende beide die regskundige en bemarkingsgemeenskappe te ondersteun wanneer handelsmerk-oortreding vermoed word. ‘n Literatuur oorsig het die elemente en vorme (besmetting en verdowwing) van handelsmerk-skending geidentifiseer asook die motivering om die konsep van ‘handelsmerk’ en die konstruk van ‘handelsmerkwaarde’ te gebruik. Die beperkings van vorige navorsing om handelsmerk-skending te meet en kommentaar op hofbeslissings het die basis van die voorstelling van handelsmerk-skending as ‘n ongewenste effek op kliënt-gebaseerde handelsmerkwaarde neergelê en dit geoperasionaliseer as handelsmerk-ingesteldheid. Handelsmerk-ingesteldheid is ‘n hoë-vlak handelsmerkwaardeskepper en vyf subkomponente (gevoelsinhoud/emosie; denke/kennis; polariteit en stabiliteit van ingesteldheid; ingesteldheidstoeganklikheid/reaksie latentheid; aankoopvoorneme) is geïdentifiseer wat handelsmerk-ingesteldheid akkuraat meet. Handelsmerk-ingesteldheid word voorafgegaan deur handelsmerk-bekendheid en gevolg deur handelsmerk-lojaliteit. Verder kan handelsmerk-ingesteldheid ook verklaar word aan die hand van vier soorte besluitnemingsprosesse: die tipe besluit (hoë betrokkenheid of lae betrokkenheid) en die tipe motivering (informatief of transformerend). Die doel van die studie was om die aard en omvang van handelsmerk-skending, (besmetting en verdowwing) op die komponente van kliënt-gebaseerde handelsmerkwaarde te ondersoek. Die studie het ‘n eksperimentele navorsingstrategie gevolg en van ‘n elektroniese opname-instrument (Qualtrics) met self-geadministreerde vraelyste gebruik gemaak. Ses hipoteses is geformuleer om vas te stel of besmetting of verdowwing ‘n effek op enige komponent van kliënt-gebaseerde handelsmerkwaarde het wanneer alle handelsmerke gesamentlik beskou word sowel as afsonderlik. Die studie was ontwerp as ‘n 3 x 2 x 2 faktoriale eksperiment. Dit het bestaan uit drie faktore (tipe skending; tipe besluit; tipe motivering) met verskillende vlakke (onbenadeel/besmet/verdof; hoë betrokkenheid/lae betrokkenheid; informatief/transformerend). Twaalf verskillende vraelyste is aan ‘n geriefsteekproef van 3 441 moontlike respondente gestuur. Die data word deur die 12 vraelyste gegenereer is met behulp van ANOVA en Mann Whitney U toetse ontleed. Die resultate het aangetoon dat besmetting ‘n statisties betekenisvolle effek op die komponente van kliënt-gebaseerde handelsmerkwaarde het wanneer die handelsmerke gesamentlik beskou word, asook dat die effek van besmetting en verdowwing verskillend is wanneer al die handelsmerke gesamentlik beskou word. Bemetting en verdowwing het statisties betekenisvolle effekte op die komponente van handelsmerkwaarde wanneer handelsmerke afsonderlik beskou word, maar die effek blyk verwant aan die tipe besluit (hoë betrokkenheid/lae betrokkenheid) te wees en nie aan die tipe motivering (informatief/transformerend) nie. Besmetting en verdowwing, wanneer dit vergelyk word, het verskillende of soortgelyke, maar veranderend invloede ten opsigte van intensiteit, effekte op die komponente van kliënt-gebaseerde handelsmerkwaarde. Die studie lewer ‘n teoretiese bydrae gelewer aan lede van die regskundige-en bemarkingsgemeenskappe. Die studie het ten eerste getoon dat handelsmerk-besmetting en –verdowwing onafhanklike konstrukte is wat verskillende of soortgelyke, maar veranderend in intensiteit, effekte op kliënt-gebaseerde handelsmerkwaarde het. Die effek van handelsmerk-skending, besmetting en verdowwing, is nie net beperk tot handelsmerk-herroeping en -herkenning en handelsmerk-ingesteldheidstoeganklikheid nie. Handelsmerk-besmetting het ook verskillende of soortgelyke, maar verskillend in intensiteit, effekte op die handelsmerke afsonderlik, wat ook geld in handelsmerk-verdowwing. Die tipe besluit (hoë betrokkenheid of lae betrokkenheid) en tipe motivering (informatief of transformerend) speel derhalwe ‘n rol in die unieke effek wat besmetting of verdowwing op die komponente van kliënt-gebaseerde handelsmerkwaarde het. Tweedens is die effek van besmetting en verdowwing nie noodwendig ongunstig nie. Trouens, verdowwing het ‘n versterkende effek op sommige komponente van kliënt-gebaseerde handelsmerkwaarde gehad, ten minste ná ‘n enkele blootstelling. Dit impliseer dat besmetting ‘n veel erger en vinniger effek op kliënt-gebaseerde handelsmerkwaarde as verdowwing het. ‘n Handelsmerkbestuurder sal na aanleiding van die studie weet hoe om te reageer, indien enigsins, wanneer ‘n junior merk verskyn wat soortgelyk aan die senior handelsmerk is. ‘n Prokureur wie se kliënt anti-skendingsbeskerming versoek sal weet, na aanleiding van die studie, of litigasie inderdaad die antwoord op die probleem is. Die studie verskaf insig, nie net ten opsigte van die aard van handelsmerkskending soos beskryf deur die impak van handelsmerkbesmetting en –verdowwing op sekere komponente van kliënt-gebaseerde handelsmerkwaarde nie, maar ook ten opsigte van die omvang van handelsmerkskending. Handelsmerkskending het ‘n effek op handelsmerke, maar die effek, of dit op ‘n sekere komponent of op die intensiteit van die effek op die kompenent mag wees, is moontlik anders as wat verwag is. Gabaseer op die resultate kan verskeie aanbevelings aan handelsmerkbestuurders en handelsmerkprokureurs gemaak word. Handelsmerkbestuurders (senior handelsmerke) behoort nie te reageer op junior merke wat hul merk (senior handelsmerk) gebruik sonder om die aard en omvang van die effek van die junior merk op die senior handelsmerk se kliënt-gebaseerde handelsmerkwaarde te bepaal nie. Eweneens behoort handelsmerkprokureurs eers die aard en omvang van die handelsmerkskending te bepaal en hul kliënte dienooreenkomstig adviseer. Sodra die aard en omvang van handelsmerkskending bepaal is, kan ‘n handelsmerkbestuurder sy reaksie volgens die geaffekteerde komponent van die handelsmerk, sowel as die intensiteit daarvan, aanpas. Prokureurs kan ten minste sommige van hul argumente om anti-skendingsbeskerming vir hul kliënte te verkry, ondersteun deur baie duidelike aanduidings van die effek van die gebruik van ‘n junior merk op kliënt-gebaseerde handelsmerkwaarde.

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Mercury speciation in solid sample matrices has been investigated using high performance liquid chromatography (HPLC) coupled with multicollector sector field (MCSF) and quadrupole (Q) inductively coupled plasma mass spectrometry (ICP-MS) for species specific isotope dilution mass spectrometry (IDMS). 199Hg enriched methylmercurychloride has been synthesised and recovered in the solid form for use as a spike material. The stability of methylmercury during the IDMS procedure was investigated using 199Hg and 13C labelled methylmercury isotopomers and ¹H Nuclear Magnetic Resonance spectroscopy. IntermoIecuJar exchange of the methylmercury halide counter ion was observed, the halide counter ion order of preference was l>Br>Cl. No evidence was found for the decomposition, or formation, of methylmercury during equilibration with soil (NIST2710 SRM) or dogfish muscle (DORM-2 CRM), or during chromatographic separation. The extent of equilibration between the spike and the particulate bound mercury compounds was studied by temporal monitoring of the 200Hg:199Hg isotope amount ratio and determining the amount of Hg species in the liquid phase. For N1ST2710, complete equilibration was only achieved when concentrated HNO3 in combination with a microwave digestion was employed. For DORM-2, complete equilibration was achieved when using 1:1 H2O.CH3OH v\v and 0.01 % 2-mercaptoethanol as the solvent, even though only 47% of the analyte was extracted into the liquid phase. The mass fraction of methylmercurychloride has been determined in E)ORM-2 and BCR464 lobster hepatopancreas CRM by two different procedures, single IDMS and approximate matching double IDMS. Mercury cold vapour generation of the HPLC column eluent allowed isotope amount ratios measurements by MC-SF-ICP-MS. For each CRM the mass fraction of methylmercury determined by the two IDMS methods was not statistically different, within the limits of uncertainty, from the certified values. An uncertainty budget for both IDMS procedures has been formulated to allow the performance of each method to be compared For single IDMS the major uncertainty contribution was derived from the within replicate uncertainty, Uwithin The combined standard uncertainty of each replicate analysis was dominated by two components, the uncertainty associated with the natural isotonic abundance 200Hg: 199Hg isotope amount ratio and the uncertainty associated with the 199Hg enriched methylmercurychloride spike mass fraction. The between blend standard uncertainty, Ubetween, was the major contributor to the expanded uncertainty for approximate matching double IDMS. The combined standard uncertainty for each individual replicate was dominated by the contribution from the standard uncertainty associated with the measured 200Hg:199Hg isotope amount ratios in the spiked sample and the mass bias calibration blend.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 69-70).
There are a variety of fuel improvement strategies being developed for spark ignition engines which use dilution. Many of these technologies use a combination of different diluents. It is impractical in optimizing these technologies to test every possible combination of diluents. The purpose of this study was to determine a relationship between the various diluents and combustion related output parameters. One of these key outputs was determining the dilution tolerance for an engine. In order to achieve this goal, the fundamental of combustion were studied. The results from this study will be useful in developing more aggressive engine control strategies. Dilution has been studied extensively in previous research. Its effects are well known. Primarily, it reduces peak combustion temperatures. This can be used as an effective means to reduce losses and hazardous emissions. Too much dilution, however, and the combustion stability is compromised. To facilitate this project, an engine was fully instrumented. Experiments were performed for a variety of operating conditions and diluents. Results were then used to correlate the diluent properties and quantities to combustion outputs. Adiabatic flame temperature was first attempted as the key metric for correlation. This metric proved to be unsuitable for developing correlations. Later, a new metric was computed by taking a linear combination of diluents. This was found to offer superior results. Using this metric along with other basic engine measurements, correlations were developed between the diluents and engine output parameters. These output parameters include dilution tolerance, exhaust temperature, NOx emissions, and combustion bum durations.
by Troy S. Niekamp.
S.M.

The next generation of balloon-borne and ground-based mm/sub-mm astronomy experiments will require operating temperatures near or below 0.1 K. When these experiments are operated remotely on platforms or at sites with limited infrastructure and maintenance sup port, a compact and reliable dilution refrigerator becomes essential. We have investigated two different dilution refrigerators in order to evaluate which system is most suitable for these applications. We have carried out a feasibility study of the simplest of the two technologies, a single-shot dilution refrigerator. A thermal model for predicting its performance has been developed, and a first prototype which achieved temperatures of about 70 mK was built. We discuss advantages and disadvantages of a single-shot system and show how minor changes to the current design can make it useful for many astronomy applications. The second dilution refrigerator is based on the principle of condensation pumping. We have built and integrated such a refrigerator with a pulse-tube cooler in order to create a completely cryogen-free system. Temperatures below 50 mK have been achieved, and temperatures below 100 mK have been maintained for more than 10 hours with several micro-Watt of cooling power. Using two 3 He sorption coolers and gas-gap heat switches we have also demonstrated how this cooler can be operated in a continuous mode. The entire system is fully automatic in operation and can be controlled and monitored remotely through a standard http protocol. We show how existing thermal models can be used to predict the cooling power and lowest achievable temperatures of the refrigerator. Experimental results are analysed and used to estimate the condensation efficiency, the performance of the heat exchangers and the 3 He circulation rate.

A new method for the quantitation of acute phlebitis in superficial veins is investigated. This method capitalizes on local temperature elevations which result from the inflammatory process. The thermally based detection method is more objective than traditional procedures which utilize simple visual evaluations of symptoms. Several irritating parenteral drugs and their vehicles as well as many commonly used cosolvents were tested for their potential to produce phlebitis. The water soluble compounds and the cosolvents produced little if any irritation. In cases where significant phlebitis was produced, it was the drug and not the vehicle which was found to be responsible. This method shows promise as a tool for screening compounds and vehicles for their potential to produce local venous side-effects. The hemolytic method for assessing the venous compatibility of parenterals was compared with the thermal method. It was found that hemolysis testing can give false positive suggestions of phlebitis, which could result in the elimination of promising new formulations. The effect of injection rate on the severity of phlebitis is investigated using parenteral amiodarone HCl. As the injection rate is increased the severity of phlebitis also increases to a limiting value. At rates above this value there is less phlebitis produced. The reason for this behavior is explained below. Amiodarone was found to precipitate upon dilution with physiological fluids. Incomplete dilution of the formulation in the blood results in a physically stable "plug" within the vein. Where there is plug flow, and the drug is soluble in the plug, there is no precipitation. It was shown in vitro that plug flow of the partially diluted formulation correlates with the decrease in phlebitis observed in vivo at rapid injection rates. The immediate precipitation of amiodarone HCl upon dilution is pH dependent. Amiodarone is reformulated in a buffered version of the original vehicle in an attempt to reduce this precipitation. Buffering the amiodarone formulation significantly improved the precipitation problem of this drug. By characterizing the variables which influence the physical stability of amiodarone we were able to produce a new formulation which is resistant to dilution-induced precipitation.

Les fluides de gisement présentent des transitions de phase qui jouent un rôle important en ingénierie pétrolière. Toutefois, la modélisation des équilibres de phase reste difficile en raison de l'extrême complexité structurelle des mélanges pétroliers. Un outil de traitement du signal délivré par le couplage CPG-SM a été développé. Il permet de distinguer plus de 2000 espèces moléculaires réparties dans 15 familles d'hydrocarbures. Parallèlement, une méthode de déconvolution matricielle a été mise en oeuvre afin de renseigner sur les proportions globales des différentes familles. Ces techniques ont été appliquées à l'idnetification d'invariances structurelles propres aux fluides de gisement et à la cartographie de potentiels chimiques de nombreux constituants dans l'espace de la composition des mélanges. Ces deux voies de recherche pourraient constituer un apport intéressant pour développer un modèle capable de prédire les propriétés de phase des fluides de gisement à partir de leur composition
Phase transition of petroleum fluids arte of fundamental importance in petroleum engineering. But modelling the phase equilibria of such fluids remains difficult due to their huge compositional complexity. A tool was developped to interpret the signal of the GC-MS apparatus used to analyse the mixtures studies in this work. This tool allowed the distinction of more than 2000 individual species distributed into 15 main families. A group type analysis method was also developped to estimate the proportions of the different families of hydrocarbons in the petroleum fractions. The techniques were used to identify compositional invariances found in natural petroleum fluids and to cartography hydrocarbon chemical potentials according to the composition of the mixtures. At term, the results of such studies could be employed to developp a model able to predict phase quilibria on the basis of their composition

In this thesis I present the design, construction, and characterization of metal powder microwave filters for a dilution refrigeration scanning tunneling microscope (STM) in the Laboratory for Atomic Imaging Research at the University of British Columbia. Scanning tunneling spectroscopy (STS) measurements performed by the STM are able to reveal features in the local density of states with energy resolution in the μeV regime if the sample and tunnel junction are cooled below 100 mK. The filters described in this work eliminate thermal noise and electromagnetic interference, which decrease energy resolution in STS measurements, up to seemingly indefinite frequency by exploiting the tremendous effective surface area of the metal powder which dissipates radio-frequency power via eddy currents induced in the grains.
Science, Faculty of
Physics and Astronomy, Department of
Graduate

Reduction in ozone levels in southern midlatitudes, caused by the transport of ozone-depleted air from the Antarctic polar vortex, is examined. The problem is approached from two different, but complementary, directions. First, a case study examining an atypical vertical profile of ozone in December 1998, caused by the presence of vortex air is presented. Second, the overall dilution effect in spring- and summer time in the years 1998, 1999, and 2000 is quantified. In the first approach, an ozonesonde profile over the Network for Detection of Stratospheric Change (NDSC) site at Lauder (45.0° S, 169.7° E), New Zealand, for 24 December 1998 showing atypically low ozone centred around 24 km altitude (600 K potential temperature), is analyzed. The origin of the anomaly is explained using reverse domain filling (RDF) calculations combined with a PV/O3 fitting technique applied to ozone measurements from the Polar Ozone and Aerosol Measurement (POAM) III instrument. The RDF calculations for two isentropic surfaces, 550 K and 600 K, show that ozone-poor air from the Antarctic polar vortex reached New Zealand on 24-26 December 1998. The vortex air on the 550 K isentrope originated in the ozone hole region, unlike the air on 600 K, where low ozone values were the result of dynamical effects. High-resolution ozone maps are generated, and their examination shows that the vortex remnant situated above New Zealand was the cause of the altered ozone profile on 24 December. The maps also illustrate mixing of the vortex filaments into southern midlatitudes, whereby the overall midlatitude ozone levels are decreased. In the second approach, to quantify the full impact of the dilution of the Antarctic ozone hole into southern midlatitudes in spring and summer of the years 1998, 1999 and 2000, diabatic RDF calculations are performed for parcels between 30° S and 60° S, initialized on a 1° longitude by 1° latitude grid, on seven potential temperature surfaces, between 400 K and 700 K. In each year, the trajectories are run back to 10 October, at which time the ozone depletion processes in the Antarctic vortex have largely ceased. Two distinct regions in the vortex, the core and the edge region, are taken into account. The reduction in ozone due to the presence of vortex parcels in southern midlatitudes is calculated in the layer between 375 K and 725 K, thus encompassing the stratospheric region where most of ozone depletion occurs and where ozone is most abundant. The calculations are performed under the assumption that the volume mixing ratio of depleted ozone (the difference between undepleted ozone and observed ozone) does not change along the trajectories. To mitigate non-conservation of mass arising from the employment of Lagrangian model, a scaling method is introduced. The results for the years 1998-2000 show that on average, between 15 October and 15 January of the following year, 17-19% of the midlatitude air parcels originate inside the Antarctic vortex. The corresponding reduction in ozone is 15-18 DU. The reduction caused by the presence of the air parcels originating in the vortex edge region is significant, especially in the early part of the period under examination. The results for four subregions in midlatitudes (spanning longitude regions of 90º, starting from 0º) are also presented, and they indicate that, on average, in the region encompassing New Zealand and Australia ozone reduction is less than in other subregions in the months of October and November, but from mid-December to mid-January the reduction is effectively the same in all subregions. Furthermore, tests to examine the sensitivity of the results to uncertainties in the wind fields, and to the choice of the initial day, are performed for the year 1998. The results indicate that the method is more sensitive to the initial conditions, including the size of the vortex and the amount of filamentation, than to introduced perturbations in the winds. The corresponding uncertainties in the midlatitude ozone reduction are 38% and 5%, respectively. The uncertainties are generally larger for subregions, and range from 37-65%, and 4-14%, respectively. The calculated ozone reduction is compared to the Total Ozone Mapping Spectrometer (TOMS) measurements of ozone column to derive relative changes in the total ozone. The results show that without the dilution effect, ozone levels in southern midlatitudes would be 4-6% higher during spring- and summertime. Moreover, a comparison of the calculated ozone reduction with ozone levels in 1979 demonstrates that on average, approximately 50-60% of the change can be attributed to the dilution effect. These results present a lower limit of the impact, as dilution in the lowermost stratosphere and troposphere is not captured in the calculations presented here.

Thesis (M.S. in Mechanical Engineering and M. S. in Applied Physics)--Naval Postgraduate School, March 2009.
Thesis Advisor(s): Driels, Morris R. ; Harkins, Richard M. "March 2009." Description based on title screen as viewed on April 24, 2009. Author(s) subject terms: GPS, DOP, JMEM, Delivery Accuracy. Includes bibliographical references (p. 200-201). Also available in print.

Orientador: Taís Maria Bauab
Banca: Sérgio Aparecido Torres
Banca: Daisy Nakamura Sato
Resumo: O Brasil apresenta uma grande diversidade de plantas medicinais, cuja utilização pela população vem aumentando cada vez mais. Byrsonima (Malpighiaceae) e Alchornea (Euphorbiaceae) que são plantas do Bioma-Cerrado do estado de São Paulo apresentam compostos com grande potencial de atividade biológica, sendo entretanto, pouco estudadas. A atividade antimicrobiana é uma etapa de extrema importância na caracterização biológica de produtos naturais com potencial farmacológico. Nossos objetivos foram investigar a atividade antibacteriana de extratos metanólicos e clorofórmicos de Byrsonima spp. e Alchornea spp empregando as técnicas de diluição em tubos e em microplacas com leitura espectrofotométrica e visual utilizando resazurina como revelador. Foram utilizadas as bactérias: Escherechia coli, Staphylococcus aureus, Yersinia enterocolitica e Aeromonas hydrophila. Nos ensaios em microplacas e em tubos foi determinada a concentração inibitória mínima (CIM) dos extratos vegetais testados à concentração de 1000æg/mL a 31,25æg/mL. Objetivou-se também comparar a eficácia das metodologias empregadas. Nosso estudo demonstrou maior atividade antibacteriana dos extratos metanólicos tanto de Byrsonima quanto de Alchornea, ressaltando os dados obtidos com B. crassa (MeOH) e B. basiloba (MeOH) que apresentaram acentuada atividade antibacteriana frente aos diferentes microrganismos testados. As metodologias empregadas foram eficazes para essa finalidade sendo as de diluição em microplacas mais vantajosas, pelo emprego de pequenos volumes principalmente os de extratos vegetais que são obtidos em pequenas quantidades. Dentre os dois métodos de microdiluição, a que empregava leitura espectrofotométrica apresentou-se mais sensível, porém a de leitura visual mostrou-se mais prática na leitura final e na interpretação dos resultados.
Abstract: Brazil presents a great diversity of medicinal plants, whose use by people increases more and more. Byrsonima (Malpighiaceae) and Alchornea (Euphorbiaceae) are plants of Bioma-Cerrado of the state of São Paulo and present composites with great potential of biological activity, but, however, they are little studied. The antimicrobial activity is a stage of extreme importance in the biological characterization of natural products with pharmacological potential. Our objectives were to investigate the antibacterial activity of methanolic and chlorophormic extracts of Byrsonima spp and Alchornea spp using the techniques of dilution in tubes and in microplates with spectrophotometric and visual readings using resazurin. Escherichia coli, Staphylococcus aureus, Yersinia enterocolitica and Aeromonas hydrophila were tested. In the microplate and tubes assays, the minimum innhibitory concentration (MIC) of plant extracts were tested in concentrations between 1000æg/mL and 31.25æg/mL. It was also compared the effectiveness of the methodologies employed. Our study demonstrated greater antibacterial activity of methanolic extracts of both Byrsonima and Alchornea, standing out the data obtained for B. crassa (MeOH) and B. basiloba (MeOH), which presented accented antibacterial activity against the different tested microrganisms. The methodologies employed were efficient for this purpose and the microplate dilution assay is more advantageous, for the fact it uses smaller volumes, mainly for those vegetal extracts that normally are obtained in small amounts. Amongst the two methods of microdilution, the one that used spectrophotometric reading proved to be more sensitive, however, the visual reading procedure was shown to be more practical in the final reading and interpretation of the results.
Mestre

In the flow distribution section of a paper machine, known as the head box, water is injected into the fiber suspension (stock) flow through a tee-mixer for more uniform production. This dilution process has two important requirements that must be fulfilled: (1) sufficient mixing so that the dilution flow spreads across the suspension flow and (2) that the injection flow rate not be so large to significantly alter the local head box flow rate. The objective of this research was to find a combination of velocity ratio and tee mixer geometry that lead to the injection flow being well mixed into the stock flow, but at the same time, the injection should not cause the total flow rate to change by more than 1%. Velocity ratios of 0.25, 0.75, 1.33, 1.5 and 2.25 were examined for four different cases of tee mixer geometries using the CFD software Fluent. Two of the cases had added contractions located near the injection point, while the other two cases had a more standard geometry with no added complexities. The pressure drop across the injection point was also measured. Mixing was qualitatively measured by simulating the injection of a passive tracer into the dilution flow. All of the results indicated that the case where the contraction was located after the injection showed the most promising results with quality mixing and lower flow rates. The cases without added contractions showed poor mixing for lower velocity ratios, and for higher velocity ratios, the flow rates were too large. The cases with contractions showed similar mixing, but the outlet flow rates produced were lower when the contraction was located after the injection instead of before it. A velocity ratio of 0.25-0.75 for the mixers with contractions produced acceptable flow rates and sufficient mixing. The simulations also showed that the static pressure for the contraction cases were nearly identical throughout the majority of the pipe. For both contraction cases the pressure drop across the injection increased with increasing injection flow rate. When the contraction was located before the injection, a pressure drop of 16% was calculated. A pressure drop of 18% to 20% across the injection resulted when the contraction was located after the injection.

Thesis (M.S.) -- University of Maryland, College Park, 2003.
Thesis research directed by: Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

This dissertation identifies the diluting effects that network society has had on the avant-garde subcultures, by first building a framework through which to understand the social structure and spatial production of the historical avant-garde, and then comparing this with contemporary avant-garde movements. The avant-garde is a cultural tradition that originated in modern 18th century Europe and North America, that critically responds to hegemonic power structures and mainstream cultural assumptions. I use the term “avant-garde subcultures” because my research focuses on the entire social group of the avant-garde. Most scholarship on the avant-garde has overlooked the importance that social relations, in particular supportive actors, and collaborative spaces have served in the creativity of the avant-garde. During the past twenty years, as society has shifted into a dependence on networked interactive technologies, the boundaries which protect these avant-garde spaces and social relations were diluted. As a result, avant-garde subcultures have entered a phase of recursively repeating themselves and culturally stagnating. I begin by reviewing the historical avant-garde and subcultures, building an overarching theory that explains that avant-garde is a type of subculture. Using past scholarship that maps the conceptual lineage from early bohemians to 1970s punk rock, I synthesize a set of traits which all avant-garde subcultures exhibit, and which can be used to build their genealogy. I then extend this genealogy to contemporary art practitioners, to prove that the avant-garde tradition continues to this day. Next, I develop a philosophical understanding of the importance of space for hegemonic power structures, based largely on the work of Henri Lefebvre. I explain how avant-garde subcultures produce spaces of representation in the cafes, bars and night clubs they inhabit, which challenge hegemony by being different from normal values and aesthetics. I reference first-hand accounts of these spaces of representation, to show how they enable the collaboration and creative thinking that is most often associated with the avant-garde. The avant-garde protect these spaces through a set of cultural boundaries: fashion, slang, esoteric knowledge, accumulation, and physical space. Manuel Castell's concept of network society depicts how hegemonic power structures have become pervasive, and thus can overcome the boundaries of avant-garde subcultures. As a result, avant-garde subcultures have increasingly become retrogressive and fluid. Some avant-garde practitioners, such as tactical media, have evolved methods for addressing these problems. While these are effective in continuing the avant-garde tradition of introducing difference, there are no adequate methods for producing new spaces of representation. I examine Eyebeam, an arts and technology center, which has since 1997 provided a space for many contemporary practitioners. While unique in its circumstances, Eyebeam has adopted several processes which have enabled it to overcome the diluting effects of network society, thereby providing a potential model for building future spaces of representation.

Cette etude a ete consacre a la determination des enthalpies de dilution en systeme micellaire en utilisant le microcalorimetre picker. La dilution des solutions de dodecylsulfate de sodium (sds) par l'eau a 298,15 k, permet de mettre en evidence la premiere transition (cmc). L'enthalpie de micellisation de ce tensioactif est tres faible. L'utilisation du cotensioactif (n-butanol ou phenol) comme sonde de son environnement a l'echelle moleculaire, a non seulement revele la presence de la premiere transition, mais aussi l'existence d'une seconde transition pour ce tensio-actif. L'etude des proprietes du n-butanol a montre qu'il est reparti dans la phase aqueuse, dans le manteau et dans le cur micellaire. A forte concentration, le n-butanol formerait une microphase stable au niveau du cur micellaire, ce qui fait de cet alcool un bon cotensioactif. Le phenol qui possede un caractere legerement acide, semble surtout etre localise au niveau du manteau micellaire: entre les ions et les contre-ions du tensio-actif. Cette disposition faciliterait l'echange entre cur micellaire et milieu aqueux, ce qui fait du phenol un cotensioactif moins marque que le n-butanol

La dilution d'un rejet flottant a la surface de la mer est due aux phenomenes de melange et d'etalement gravitaire. A partir de la litterature, on presente des jets de surface gaussien (chu, et lirka 1986), les phenomenes gravitaires (britter et simpson, 1978), et les modelisations locales. Des modeles numeriques permettent de simuler: le comportement global du jet, les effets gravitaires essentiellement sous forme d'un bicouche, ou l'ensemble des phenomenes traites localement. Ces modeles sont analyses. D'importantes campagnes d'investigation sur sites ont ete menees dans le panache de la centrale de gravelines (thermographies aeriennes infrarouge, et de capteurs fixes). Ces campagnes sont analysees. En jusant le jet s'etale librement, en flot il est ecrase contre la digue du port. Aux renverses un melange rapide s'effectue. Le jet presente les caracteristiques gravitaires attendues. Pour le melange: les lois traditionnelles liees a la turbulence de cisaillement sont insuffisantes a la renverse et dans les fronts. Pour la baie de daya, sur la base d'investigations sur site une climatologie generale est proposee qui met en evidence l'influence de la mousson et l'apparition de stratification thermique et saline. L'etude de la dilution d'un rejet est menee en combinant ces elements et les caracteristiques des modeles disponibles. En conclusion, on souligne l'importance d'une approche pragmatique de la modelisation et de la connaissance des conditions de site. De plus, on propose des domaines de recherche, en particulier sur les lois de melange et de turbulence

La tesi tratta della gestione strategica del brand, focalizzandosi sull’opportunità di adottare politiche di brand extension e sui pericoli derivanti da tali scelte che si manifestano specificatamente nella perdita di brand equity, a sua volta dovuta a quella disfunzione che in dottrina prende il nome di brand dilution.

This thesis investigates the laminar flame speed of C₁-C₃ alkanes and their binary mixtures at conditions of interest in natural gas based gas turbines viz. high temperature, pressure and dilution. Laminar flame speed has been found useful not only for validating chemical kinetics mechanisms but also for developing empirical scaling laws for practical combustion systems. The thesis addresses the lack of laminar flame speed data of C₁-C₃ alkanes at preheat (300-650 K), pressure (1-10 atm) and significant oxidizer dilution (15-21 vol% O₂). Over 400 measurements are reported over a wide range of conditions along with comparison to predictions from leading chemical mechanisms. Unstretched flame speed measurements were performed using a modified Bunsen flame technique based on reaction zone area from chemiluminescence imaging, whereas the strain sensitivity measurements were performed using a bluff-body stabilized stagnation flame with high resolution PIV. These measurements are used to: (i) discern the uncertainties associated with the measurements, (ii) understand the effect of fuel mixture and vitiation on flame speed, and (iii) validate the performance of the leading chemical kinetics mechanisms. Extensive testing shows the unstretched flame speed measurements from the modified Bunsen technique are reasonably accurate. Vitiation studies for methane and propane flames at high preheat show the reduction in flame speed results primarily from the thermal effect of the diluent and that the relative change in flame speed from the undiluted mixture is well correlated to the fractional change in the adiabatic flame temperature over a range of conditions. Significant difference in the measured and predicted flame speeds were observed for rich, atmospheric pressure, propane and lean, high pressure, methane/ethane mixtures with dilution. This highlights possible avenues for improvements in the chemical kinetics mechanisms. Systematic errors were also identified in the Bunsen flame measurements at certain conditions, such as for rich flames with dilution, indicating a need for better understanding of the Bunsen flame technique at these conditions. The difference in the measured and predicted flame speed does not show any clear correlation with the flame height or the strain sensitivity of the mixture. Finally previously proposed mixing rules for estimating flame speed of fuel mixtures from pure fuel components are shown to be reasonably accurate over a range of pressure, reactant temperature and dilution conditions.

Selon l'hypothèse de l'effet de dilution, les écosystèmes les plus riches en espèces seraient également les moins propices à la circulation des agents infectieux du fait de la présence d'hôtes non compétents constituant des impasses épidémiologiques. Dans cette thèse, nous explorons l'existence de ce phénomène sur le modèle des leishmanioses cutanées zoonotiques en Guyane. Des outils moléculaires basés sur l'utilisation des technologies de séquençage haut-débit ont été développés pour étudier le système épidémiologique. Ces outils ont ensuite été employés pour caractériser le cycle de transmission des leishmanioses dans des sites forestiers sujets à différents niveaux de perturbation d'origine humaine. Nos résultats semblent globalement congruents avec l'hypothèse de l'effet de dilution, et indiquent un risque infectieux plus élevé sur le site le plus perturbé. Toutefois, les différences observées entre les sites ne sont pas significatives et d'avantage de données seraient nécessaires pour tirer des conclusions générales
The dilution effect hypothesis states that more diverse ecological communities are less prone to pathogen transmission because of the presence of non-competent hosts acting as epidemiological dead-ends. In this work, we investigate the existence of this phenomenon in the case of zoonotic cutaneous leishmaniases in French Guiana. Molecular tools based on high-throughput sequencing technologies have been developed to study the epidemiological system. These tools were employed to explore leishmaniases transmission cycles in forest sites undergoing different levels of human-induced perturbations. Our results seem generally congruent with the dilution effect hypothesis, indicating higher disease risk in the most perturbed site. However, differences observed between sites were not significant, and more data is needed to draw general conclusions

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics
Social studies suggest that adding obviously irrelevant product information to diagnostic information mitigates consumers’ judgments of products, a concept named dilution effect. This study shows that expert consumers are not only less subject to the dilution effect than novice consumers but it also suggests that experts are in fact shielded against the effects of irrelevant information. In addition, this project was also able to demonstrate that irrelevant information may be positive for brands to communicate when the target is not an expert in the product category and the irrelevant information is somewhat abstract and vague. As irrelevant information becomes more concrete, consumers with low expertise will be subject to the dilution effect whereas experts will remain unaffected.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.
This research study focuses on creating a drill pattern for the Condestable mine, which will allow us to assess the percentage of dilution. For these purposes, we used the Pearse formula proposed in 1955, which allowed us to find the burden and later, the spacing that each drill hole should have in the pattern. Once we had collected all the numerical data, we used the JK SimBlast program to design the proposed drill pattern and analyze the damage zones, the tonnage acquired and the existing dilution. According the results obtained, the smaller the hole diameter, the less dilution will be generated when diversifying the wall and ceiling explosives.

Many external parties such as investors, creditors, and regulatory agencies, use a company’s financial statements in their decision-making. In doing so, they rely on audit opinions on whether financial statements are fairly stated. However, evidence suggests that there are factors in the audit environment that influence auditor judgments. For example, nondiagnostic client information dilutes auditor judgments when compared to judgments based on diagnostic information alone, especially for less experienced auditors (Hackenbrack 1992; Hoffman and Patton 1997; Glover 1994; Shelton 1999). High time pressure conditions mitigate this effect by refocusing auditor attention toward relevant client information, therefore reducing the impact of nondiagnostic information (Glover 1994, 1997). This research study examines other common audit environment factors to determine if they too influence audit judgment results. An online questionnaire of 149 auditors, CPAs and other accounting professionals indicate that the inclusion of nondiagnostic client information results in a significant change in auditor judgments. The direction of this change follows a theorized pattern; risk assessments that were initially high are reduced, while those that were initially low are increased. Significance was not consistently found for a workload and PCAOB effect on auditor judgment. However, a comparison of the absolute value of dilution effect means across conditions reveals some trending for the proposed unwanted effect of high workload, and the beneficial effect of PCAOB guidance. These results have important implications for auditing research and practice. It extends previous archival research on workload effects and uses a unique questionnaire design to reexamine workload pressures in a behavioral setting. The results of hypothesis testing on workload pressure and PCAOB guidance, although lacking consistent statistical significance; exhibit trends that agree with proposed theoretical relationships. Tests on the effects of nondiagnostic information show strong statistical support for previous studies in the area of psychology and audit. This study’s greatest contribution suggests that audit pressures do not produce equivalent effects on auditor judgment; time pressure improves audit judgment, while workload pressure does not (Glover 1994, 1997). These results can be explained by examining the relationship between stress and audit judgment performance (Choo 1995, Yerkes and Dodson 1908). Different types and different degrees of audit pressures may correspond to different levels of audit pressure. Low to moderate levels of audit pressure, such as the level of time pressure used in Glover’s (1994, 1997) study improve audit performance. Higher audit pressures, such as high workload during an auditor’s busy season, may lower audit performance.

Unplanned ore dilution or stope overbreak, which has a direct and large influence on the cost of a stope, and ultimately on the profitability of a mining operation, can be attributed to both the mining process and to geologic setting. The research undertaken in this document, applicable to a wide range of underground mines employing the blasthole mining method to extract tabular orebodies, focuses on examining factors attributable to the generation of unstable stope hanging-walls.
The primary objective of the research undertaken is to establish new models for stope and orezone design, with respect to anticipated stope overbreak, focusing on the position and type of stope within the orezone extraction sequence. Identified factors influencing unplanned dilution, such as: induced stress environment, stope geometry, and the setting of individual stopes are considered.
The research undertaken incorporates a variety of components, including (i) parametric 3-D numerical modelling to examine influences of individual factors on hanging-wall overbreak, (ii) case example analysis, and (iii) orezone extraction sequence simulation, using 3-D elastic numerical modelling. Design criteria, developed from the parametric modelling, was applied to the orezone sequence modelling to develop trends for stope dilution, as functions of stope design and construction.
It was found that hanging-wall overbreak is not significantly influenced by depth alone, and that stopes with large vertical and short horizontal dimensions or stopes having long horizontal and short vertical dimensions are more stable than large square-like stopes. Also, through parametric and case studies, it was demonstrated that, in addition to stope dimension, the amount of unplanned dilution differed according to stope type. Five stope types were identified, based on their position within a tabular blasthole mining sequence. Measured overbreak varies with stope type, with secondary stopes generating a greater volume of hanging-wall dilution than do primary stopes. A pillarless mining sequence will generate less overall dilution than a primary stope: secondary pillar mining sequence.

Ce mémoire rend compte d’une étude avec un minerai aurifère pour quantifier l’effet de la dilution excédentaire sur l’extraction de l’or. Depuis une quinzaine d’années, une tendance d’augmentation de la profondeur des mines souterraines est observée au Canada et dans le monde. Lorsque ces exploitations souterraines atteignent des profondeurs supérieures à 1000 m, elles deviennent sujettes à de fortes pressions et tensions causées par la roche. Cependant, l’effet résultant sur l’extraction du minerai est difficilement quantifiable occasionnant une dilution opérationnelle excédentaire à celle planifiée. Le projet de maîtrise analyse l’impact de cette dilution excédentaire sur le traitement du minerai d’une mine d’or située dans la région de l’Abitibi (nord-ouest du Québec). Pour ce faire, deux types de dilution sont considérés : la roche stérile et le remblai. Les résultats du test de Bond et de données de cyanuration issues de la littérature illustrent dans quelle mesure le taux d’alimentation peut être augmenté pour mitiger l’effet de cette dilution excédentaire et la perte de production en or. La discussion étudie également les points positifs et négatifs du montage conçu pour l’automatisation de la cyanuration du projet.

Magister Legum - LLM
The rights relating to a trademark are said to be found in the fact that proprietors have acquired goodwill and a repute in their mark. Trademark law has always protected that aspect of what a trademark embodied, inter alia, to serve as a symbol of where a product originates from and guarantee quality by the setting the registered trademark proprietor’s goods apart from those of his competitor. The dilution of a trademark is one of the most challenging issues facing the sphere of trademark law in South Africa. Trademark proprietors have in the past relied successfully on primary and secondary or extended infringement. There has, however, been a dearth of cases on infringement by dilution thus far. The research in this study will primarily take the form of an evaluation of the development of the anti-dilution action and why there is dearth of successful cases in South Africa. Trademark proprietors are at risk of suffering financial loss if they are not able to protect their marks from dilution. The thesis will make recommendations whether the dilution provision contained in the Act need reform or whether the approach to the application of the anti-dilution provisions by our judiciary needs to change.

La présente thèse, concernant l’ingénierie de la photosynthèse naturelle et notamment l’optimisation des procédés de production de microalgues, a été menée à l'Institut Pascal. L'approche suivie repose sur la construction de modèles de connaissance des photobioréacteurs, capables d'en prédire les performances quelle que soit leur géométrie, les conditions d'éclairement, ou le type de microalgues cultivées. Ces modèles de connaissance permettent de dégager des stratégies de conception et de conduite du procédé, qui sont utilisées pour développer et réaliser des démonstrateurs performants, à l'échelle pilote. Cette thèse a pour objet d'étude un photobioréacteur pilote de 24 litres utiles à agitation pneumatique dans lequel la lumière est apportée dans le volume réactionnel par 1000 fibres optiques à diffusion latérale. Sa conception repose sur le principe innovant de Dilution Contrôlée du Flux solaire en Volume (DiCoFluV) dont l'objectif est d'atteindre l'efficacité thermodynamique maximale de la photosynthèse. Au cours de cette thèse, le réacteur a été étudié en conditions d’éclairement parfaitement contrôlées, grâce à des lampes à décharges. Il a été rendu fonctionnel (en incluant sa régulation et son amélioration), puis caractérisé en termes d'hydrodynamique et de transfert radiatif. Notamment, le flux radiatif incident à la surface des fibres optiques a été déterminé par des expériences d'actinométrie (sel de Reinecke), grâce à un traitement original permettant l'analyse de situations avec absorption partielle du rayonnement et en géométrie complexe. Ensuite, une année de culture ininterrompue de la cyanobactérie Arthrospira platensis (dont six phases de fonctionnement continu) ont permis de mesurer la vitesse volumétrique moyenne de production de biomasse et l'efficacité thermodynamique du pilote. Pour les faibles densités de flux testées (dilution), les résultats expérimentaux ont montré l’apparition d’un phénomène de photorespiration qui a été intégré dans le modèle de couplage thermocinétique. De plus, ce manuscrit présente également l'utilisation de la méthode de Monte Carlo pour la résolution des modèles radiatifs dans la géométrie réelle du procédé, définie à partir d’une conception assistée par ordinateur, ce qui est une nouvelle avancée pour le traitement des géométries complexes. Après validation de l'adéquation entre les mesures expérimentales et l'estimation prédictive par le modèle, des premières simulations du pilote en fonctionnement solaire ont été menées, à partir de bases de données solaires (DNI). Les résultats obtenus donnent des premières indications quant aux paramètres d'ingénierie (en particulier le facteur de dilution) menant à une productivité surfacique moyenne annuelle maximale, en fonction de l'implantation géographique
The present PhD dissertation deals with photobioreaction engineering for efficient microalgae production. The approach is based on the construction of knowledge models that permit predicting the performances of the process, whatever its design, the illumination conditions, or the microalgae species cultivated. These models are used to establish optimal design and control strategies that are implemented to construct and operate pilot-scale plants. Here, a 24 liters air-lift photobioreactor is studied, that is based on the principle of incident solar light-flux dilution for approaching the maximum thermodynamic efficiency of natural photosynthesis. For that purpose, the culture volume is internally illuminated by 1000 light-diffusing optical fibers. As a first step toward solar production, this PhD work focuses on perfectly controlled illumination conditions ensured by discharge lamps. First, the reactor hydrodynamics and radiative transfer are characterized. In particular, incident light-flux density at the fiber surfaces is measured by actinometry (with Reinecke salt), thanks to a novel treatment enabling analyses of situations with partial light absorption and complex geometries. Then, the mean volumetric rate of biomass production and the process efficiency are measured based on one year of continuous Arthrospira platensis culture. For the low radiative flux densities tested (dilution), photorespiration by the cyanobacterium is observed and included in the thermokinetic model. Moreover, this dissertation includes a presentation of the Monte Carlo method for solving the radiative transfer equation withinthe complex geometry of the computer aided design used for manufacturing the reactor. After validation against experimental results, the model is predictively used to simulate the pilot operating with natural solar light, based on solar DNI databases. These results indicate engineering parameters (in particular the dilution factor) for optimal yearly-averaged surface productivity, as a function of Earth location